Pros: Industrial strength, spraying options included, compressor compatible, one charge will empty vessel without pumping
Cons: Poor ergonomic shoulder strap placement, maybe too complex for simple homeowner use
Most homeowners have the occasion to mix some chemicals, be they pesticides, herbicides or others, and apply them to their intended target. Broadcast application of a selective herbicide might be in order for the lawn, the oaks might need a spot fungicide, the armyworm invasion may need a little more firepower brought against it than a simple spray bottle. You may even desire an application of detergent or house cleaner, and a bucket is not going to get it done. Things as they are, almost every homeowner can find use for a pump sprayer, and many times the pump sprayer will save time and trouble as it fulfills the many roles for which it is designed.
Selection of a pump sprayer might not seem that daunting, but like anything else, you can spend a little, or you can spend alot, on a relative scale. Features run the gamut, from capacity, application options, PSI, construction features (longevity is the concern), etc. They also offer many types of sprayers, from the back pack style, to the motorized pump, the metal tank, the plastic tank, etc. For the average homeowner, the vertical hand-carried pump sprayer is going to be the most cost effective choice, and in this realm, the Solo 457 is a brute of a product.
The Solo features: This unit is made up almost entirely of a very heavy grade plastic. There are a couple of metal parts, the most evident is the Schrader valve body near the filler neck of the unit. This valve, identical to the valve on your car's tires, allows you to use an air compressor to pressurize the tank. The strap handles are also metal, a nickel type steel, that will corrode if not rinsed thoroughly after use. The unit features a hand pump assembly in the very substantial lid, a lid that screws down onto the tank with course threads, making an airtight seal. The spray wand hose is 36" long, and the wand is another 30" long. The wand's actuator is a compression valve similar to what you would find on a gas pump, pull up to engage spray, and let go to stop. There is also a "constant on" feature that allows you to continuously spray without compressing the spray valve actuator. The unit is shipped with three different wand options, the fan spray, the conical spray, and the variable wand tip (good for getting high into trees). Opposite the Schrader valve is a check valve that will release tank pressure in excess of 45 PSI.
Using the Solo: The use of this product is pretty straight forward. You must first determine the method you desire to apply the spray, and adjust the tip head for that spraying. Say you desire to fan spray broadleaf weeds in your yard, now is the time to swap out the sprayer nozzle, and be sure to use the required o-rings. The o-rings are shipped with the nozzles, and care must be taken not to lose them, or you will be calling Solo for replacements.
Mixing the contents is easy, measure your product to the desired dilution, and fill the tank accordingly. Tank capacity on the 457 is 2.0 gallons U.S.
Hand pump the tank, or use an air compressor. If you put 45 PSI into the tank, it will be sufficient pressure to empty the tank at a very constant rate until it is practically empty. This is a big selling point for the Solo product, consistency. The tank's nature is such that it can supply sufficient pressure to complete a tank's worth of application without re-pumping. The same holds true for hand-pumping, although you may find hand pumping 45 PSI into the Solo quite a chore. It probably takes a couple of hundred strokes to get it hand pumped to that pressure, and you'll know when it's there when the check valve gives way.
Some problems: The Solo is a very good product, but not without its problems. One of the things I don't like about it is when I am pumping the unit to its operating pressure, the check valve gives way. This tells you it is fully pressurized, but you'll also get a mist of the contents in a little cloud directly above the sprayer. If you're applying 2-4,D, a herbicide, you'll probably not want to breathe those fumes. Also, if you sling the unit over your shoulder, the strap can get fouled in the check valve, causing a release of pressure, and a cloud of whatever your spraying to come out of the valve. I've mitigated this by carrying the unit by the handle in its locked position, but this in inconvenient for my wife, due to the weight. She's purchased a much smaller sprayer to handle her garden tasks, but I still require the larger capacity sprayer to handle lawn duties. Changing nozzles can be a bother, especially mid-stream. If you decide to change mid-stream, use the utmost caution not to contaminate yourself with whatever you are spraying. Have running water nearby to rinse the nozzles and your hands, and use rubber gloves. One last thing, sometimes it requires superhuman strength to uncork the top of the sprayer after a spray detail, even after releasing pressure. I believe the threads come under pressure as the unit is pressurized, and this makes it more difficult to unscrew the top. Sometimes you just have to get Superfly TNT with it to get it undone, but it's not impossible.
Why it is good: This sprayer will help you make bulk applications that you deem necessary, with little fuss and superior efficiency. When it is pressurized, you can put out some product in serious quantities without stopping to re-pump. The heavy-duty construction will have this sprayer in your shed for many, many seasons.
A word of advice: Always follow the manufacturers instructions when working with chemicals and chemical applicators, and use protective clothing, gloves, long sleeves and pants. Try to apply chemicals in fair weather, and take charge of your surroundings concerning pets and children. Use the minimal chemical application necessary to reach your desired end.
Also, triple-rinse your sprayer and associated gear to sanitize it until its next use.
The Solo product is definitely professional grade, and is worthy of your consideration. Good luck and green grass.